The Science Journal of the American Association for Respiratory Care

2005 OPEN FORUM Abstracts


James Stegmaier RRT-NPS, RPFT, CCM, Douglas Laher BSRT, RRT, Jennifer Laing RRT, Mansoor Ahmed, MD, FCCP Health Aid of Ohio, Lutheran Hospital, Southwest Cleveland Sleep Center Cleveland, Ohio

Background: Most standard Continuous Positive Airway Pressure (CPAP) devices utilize a variable speed blower to provide a constant pressure. Increases in mask pressure on exhalation can occur up to 2 cmH20 above the prescribed pressure in the early portion of exhalation if the motor speed cannot rapidly decrease to compensate for the increased pressure. Anecdotally expiratory pressure increases have been suggested to cause patient discomfort and a decrease in compliance. SoftXT Unloading (Invacare) is a method of decreasing the duration of the rise in expiratory pressure above the prescribed pressure. SoftXT uses variable resistance valve technology, fixed blower motor speed and software algorithms to continuously monitor and rapidly shunt airflow away from the patient when pressure increases are detected. By decreasing the duration of expiratory pressure rise, it is theorized to improve expiratory comfort and resistance for the patient which would lead to improved compliance with the therapy.

Method: 40 patients diagnosed with Obstructive Sleep Apnea and prescribed CPAP therapy were setup on a Polaris EX CPAP (Invacare) with SoftXT. 20 patients utilized the therapy with the SoftX Unloading engaged at the maximum setting and a control group of 20 patients were setup with the technology turned off. Patients were randomly selected for the study or control group with equal number of patients selected with prescribed CPAP pressures above and below 10 cmH20. All 40 patients studied used the appropriate size ComfortGel nasal maskT (Respironics) and a Polaris EXT (Invacare) heated humidifier. All patients received the same instruction and written educational materials. Compliance was measured at 7, 14, 30 and 60 days.


CPAP Pressure < 10 cmH20 - Average Nightly Usage

7 days 14 days 30 days 60 days
Study Group - SoftX Unloading Engaged 366 min 396 min 378 min 360 min
Control Group 354 min 360 min 336 min 354 min

CPAP Pressure > 10 cmH20 - Average Nightly Usage

  7 days 14 days 30 days 60 days
Study Group - SoftX Unloading Engaged 354 min 378 min 384 min 384 min
Control Group 330 min 300min 294 min 306 min

Conclusions: The study group compared to the control group with CPAP pressures less than 10 cmH20 demonstrated only an average increase of 6 minutes of usage when the SoftXT is engaged after 60 days of usage. In patients with prescribed pressures greater than 10 cmH20 there was an average increase of 78 minutes of usage when the SoftXT was utilized. The results indicate no significant improvement in compliance when the CPAP pressure is less than 10 cmH20 but substantial improvement in compliance was demonstrated when the CPAP pressure was greater than 10 cmH20 with the Unloading technology after 60 days. Further investigation including a larger number of patients, longer period of compliance monitoring and other factors which influence compliance is needed to substantiate these preliminary findings.